> For the complete documentation index, see [llms.txt](https://ankang.gitbook.io/commons/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ankang.gitbook.io/commons/commons-beans/ru-men/bei-jing.md).

# 背景

在分层应用的开发过程中，开发人员需要针对各层的特点封装不同的数据对象，如：VO（View Object，展示层对象）、DTO（Data Transfer Object，数据传输对象）、Entity/DO（Data Object，数据层对象）等。随之而来的就是数据对象的转换需求。

#### 在不同层次的数据对象拷贝过程中，常用的处理方式有：

* 手动拷贝：
  * 优点：代码可控性强，可以避免复杂对象拷贝的潜在问题
  * 缺点：编码复杂，后期维护难，字段容易有遗漏
* Spring/Commons的BeanUtils：
  * 优点：使用简单，轻量
  * 缺点：只能处理简单的字段，无法处理复杂的映射
* Dozer等映射框架：
  * 优点：开源，有很多项目实践检验
  * 缺点：不一定符合项目需求，对懒加载支持不好，扩展/修改困难

为了简化开发人员的工作，解决现有方案存在的问题以及更好地适应项目需要，commons-beans项目应运而生。


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